Study of Geometrical, Electronic Structure, Spectral, and NLO Properties of Phenyl-Based Azo Dyes of Dye Sensitizer for Solar Cells: A Theoretical Study

The molecular geometry, electronic structure, and absorption spectra of some important phenyl derivatives are investigated by using DFT and TD-DFT with B3LYP and CAM-B3LYP functional. The highest HOMO–LUMO energy gap, Non-linear optical properties of dipole moment, polarizability, and hyperpolarizability are calculated. In both methods hyperpolarizability PDP values (16.77 × 10⁻³⁰ and 16.59 × 10⁻³⁰ esu) are higher than PDNA, PDN, and MPAN dye. The Molecular electrostatic potential shows that PDNA dye has more electronegative potential. Comparing all the dyes, PDP dye shows a higher light harvesting efficiency in the UV–vis region. The vibrational frequencies are assigned based on the potential energy distribution (PED) using the VEDA-4 program.